Low pressure fuel air injection and ignition system



`lune 24, 1941. I E-0NARD 2,246,998 Low` PRESSURE FUEL AIR INJECTION AND IGNITION SYSTEM Filed Oct. 4,' 1958 3 Sheets-Sheet 1 `lune 24, 1941. s,'w LEONARD 4 2,246,998

.LOW PRESSURE FUEL AIR INJECTION AND IGNITION SYSTEM 4Filed oct. 4, 1958 s sheets-sheet 2 A iibrneys June 24, 1941. l Q W LEONARD 2,246,998

Low RESURE FUEL AIR INJECTION AND .IGNITION SYSTEM.

' Filed oct. 4,/19548 s sheets-sheet 3 In ventor Attorney.

Patented June 24, 1941 UNITED STATES PATENT OFFICE LOW PRESSURE FUEL AIR INJECTION AND IGNITION SYSTEM Stehman W. Leonard, Martinsburg, W. Va.

Application October 4, 1938, Serial N0. 233,268

3 Claims.

The' present invention relates. to fuel air injection and ignition system for internal combustion engines and has for its primary object to provide a low pressure fuel air chamber mounted on the engine cylinder adjacent the high pressure chamber of an internal combustion engine, 'the low pressure and high pressure chambers having communication through mechanically operated or other 'suitable type valves and adapted to be moved in an open position slightly in advance of the completion of the compression stroke of the piston of the engine to admit the highly compressed air in the combustion chamber into the low pressure chamber to ignite the fuel therein for combustion purposes.

An important object of the present invention is to provide a low pressure fuel air injection and ignition system of this character designed primarily to eliminate the-complicated fuel pump injectors and metering devices as at present employed in Diesel type engines whereby to improve the engine mechanically as well as to reduce the cost of manufacture thereof.

Other objects and advantages will become apparent from the following detailed description when viewed together' with the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout and in which Figure 1 is a transverse sectional view through an internal combustion engine illustrating a practical application of the invention.

Figure 2 is a fragmentary longitudinal sectional view.

Figure 3 is a top plan view.

Figure 4 is a side elevational view of the engine head.

Figure 5 is a transverse sectional view of a four-cycle engine embodying the present invention, and

Figure 6 is a fragmentary side elevational view of the engine head for the four cycle engine.

Referring now to the drawings in detail wherein for the purpose of illustration I have disclosed a preferred embodiment of the invention the numeral 5 designates an internal combustion engine generally which includes one or more cylinders 6 having a piston 1 operable therein, the upper portion of the cylinder constituting the high pressure or combustion cham- -ber as at 8.

Secured to the top of the engine is a head 9 having a low pressure chamber I0 formed therein adjacent it's bottom portion and communicating with the high'pressure chamber 8 by means of an opening I I which forms a valve seat and vwith which is associated a poppet. type valve I2.

The valve I2 extends upwardly through the top of the head and is actuated by the usual type of rocker arm I3 pivotally mounted on a bracket I4 secured to the top of the head and operatively engaged by a push rod I5 extending vertically at one side of the engine for operation by a conventional type of cam shaft (not shown).

The head 9 is also provided with a fuel air intake port I6 communicating with a manifold I1 secured to one side of the head and with which a fuel air feed pipe I8 communicates.`

The port I6 communicates with the lower pressure chamber I0 by means of an opening I9 which forms a valve seat and with which a poppet type valve 20 is operatively associated and which alsol extends through the top of the en gine head and is likewise operated by an individual rocker arm and push rod of the type heretofore described.

Air intake and discharge ports 2I and 22 are formed in the sides of the engine for admitting air into the cylinder 6 upon the completion of the down stroke of the piston 1 in a manner well known in the art.

The invention is adapted for.use upon either two-cycle engines, as illustrated in Figures 1 to 4 inclusive of the drawings, or upon four-cycle engines as illustrated in Figures 5 and 6 of the drawings, the cycle of operation for the fourcycle Diesel type engine being as follows:

On the intake stroke of the piston, air is drawn into the cylinder through the intake valve 21 cooperating with valve seat 28 from which the passage 29 leads through the head to the air intake pipe 30 which communicates with the atmosphere (or to a supercharger). The exhaust isaccomplished through the valve I2 cooperating with the valve seat II communicating with the low compression chamber' I0, the latter being also provided with the` exhaust valve 3I cooperating with valve seat 32 controlling communication to the exhaust pipe 33 through the passage 34.

As the piston 1 moves downwardly on the intake stroke the valve 21 opens admitting pure air to the engine either under pressure (or at atmospheric pressure), 'valves I2, 20 and 3| being closed on this stroke. As the piston 1 starts upwardly on the compression stroke the valve 21 also closes thereby causing a compression of air in the chamber 8 to 16 to 1 plus ratio (so as to maintain the 16 to 1 ratio when valve I2 opens). A few degrees before top center is reached valve I2 opens admitting highly compressed hot air into the low compression chamber I0, valves 20, 28 and 3| being closed at this time. Ignition takes place, forcing piston 1 downwardly andas the pistonstarts upwardly on the exhaust stroke the lexhaust valve 3| opens (valves 21 and 20 being closed at this time) and theburnt gases are forced out of the chamber 8 through valve I2 into chamber I0 and out through exhaust valve 3| into exhaust passage 34 and exhaust pipe 33,

thereby clearing both chambers of burnt gases, and as the piston starts downwardly again on the intake stroke. the valve 21 opens admitting pure air to the cylinder. At this time the valves I2 and 3| are closed and valve 20 is open, admitting fuel-air mixture under prsure from the manifold i1 through the passage I6 in the motor head to the low pressure chamber I0.

At this point let it be understood that by keeping the intake valve 21 closed and the valve I2 open Vduring a portion of the intake stroke, that a partial vacuum is created in chambers 8 and I (at this time valves 20 and 3| being held closed) whereupon valve I2 closes and valve 21 opens so that air is admitted into the'compression chamber before starting the compression stroke. As the piston 1 moves upwardly compressing air in the compression chamber, the valve 20 opens and due to partial vacuum in chamber I0, little or no air pressure is required communication to force the fuel-air mixture into the chamber I0 from the passage I6. By reason of this construction the use of an air compressor is not necessary and permits the use of an ordinary type of gasoline engine carburetor where gasoline is used as the fuel. At present gas engine compression ratios are not practical .above '7 to 1 due to pre-ignition of fuel and gasoline as a fuel is not practical for compression ignition engines, due to the fact that it carries insuiiicient lubricating qualities for the present injection equipment and accordingly, the present invention makes it possible to use the gasoline for fuel and to employ conventional types of gasoline carburetors at compression ratios of compression ignition engines.

In the two cycle type engine, ordinarily employing no valves, but `lntaking and exhausting through the ports 2| and 22, on the intake stroke or while the piston is at the bottom of the cylinder the intake port 2| is open and air is admitted into the cylinder at atmospheric pressure or may be boosted by supercharger if desired. When the piston approaches within a few degrees of top center the air is compressed to approximately 400 pounds per square inch which causes an increase in the temperature of the air to approximately 1,000 degrees F.

While the piston was at the bottom of the cylinder and the air being admitted thereto the intake valve from the fuel air manifold opens and admits fuel air mixture into the low pressure chamber lwhile the exhaust valve between the chambers is closed. As the piston reaches the top of its stroke the exhaust valve from the low pressure chamber opens admitting the heated air from the combustion chamber into the low `pressure chamber causing ignition of the gases and producing thepower stroke as above explained. The exhaust port 22 is uncovered upon the down stroke of the piston as well as the intake port 2|, the incoming air forcing out the exhaust gases as completing the two cycles of the two cycle engine.

It is believed the details of construction and manner of operation of the device will be readily understood from the foregoing without further detailed explanation.

What is claimed is:

l. In an internal combustion engine, a cylinder having a combustion chamber and an air low pressure chamber, said low-pressure charnber being relatively ,shallow and of a diameter substantially equal to that of the cylinder and adapted for preheating and vaporizing fuel admitted thereto, a valve between the low pressure chamber and the feed chamber and a valve between the combustion chamber and the low pressure chamber, said valves arranged for opposite opening and closing movement and said last named valve being adapted to provide between the combustion and low-pressure chambers at the approach of the peak of the compression stroke of the piston for utilizing the highly compressed air in the combustion chamber to ignite the fuel-air in the low pressure chamber.

2. In an internal combustion engine, a cylinder having air intake and discharge ports, a piston working in the cylinder, theupper end of the cylinder constituting a combustion chamber, a head closing the top ofthe cylinder, a

low pressure fuel-air chamber in the head said low-pressure chamber being relatively shallow and of a diameter substantially equal to that of the cylinder and adapted for preheating and vaporizing fuel admitted thereto, the bottom of the head forming a bottom wall for said low pressure chamber and the top wall of the cylinder, a valve in said wallA controlling communication between the chamber and cylinder, a fuel intake manifold in the head above the low pressure chamber and a valve controlling communication between the manifold and low pressure chamber and arranged for opening and closing movement opposite to said first named valve whereby to admit and retain fuel under low pressure in the low-pressure chamber for contact with air compressed in the combustion chamber to ignite said fuel.

3. In an internal combustion engine including a cylinder having air intake and discharge ports communicating with the cylinder thereof, a piston operable in the cylinder, a head for the engine closing the top of the cylinder, said cylinder, beneath the head constituting a combustion chamber, a relatively shallow low-pressure f to said low-pressure chamber, 4a valve between the manifold and the low-pressure chamber, said valves being arranged for opposite opening and closing movement and said piston being adapted to compress air in the combustion chamber to a predetermined pressure capable of igniting the fuel-air in the low-pressure chamber upon contact therewith.

STEHMAN W. LEONARD. 

